A rescue operation was underway Friday for a "significant number" of migrants on board a semi-sunken boat in the Mediterranean south of Crete, Greek authorities said, with about 250 people rescued so far.
The coast guard said the roughly 25-30 meter (82-98 foot) vessel, which resembled a large fishing boat, had been carrying an undetermined number of people when it was located Friday half-sunk about 75 nautical miles south of Crete in international waters.
Greece was sending two patrol boats and two helicopters, while four ships that had been sailing nearby were participating in the rescue operation.
It was not immediately clear where the boat's passengers were from, or where the vessel had set off from or was heading to.
The coastguard said the boat, carrying an undetermined number of people, was located about 75 nautical miles south of Crete in international waters.
Four nearby ships were participating in the rescue operation, while two Greek patrol boats and two helicopters were on their way.
The short crossing from the Turkish coast to Greek islands was the preferred route for migrants heading to Europe until Balkan countries closed their borders.
The number of people attempting to head to Europe from the north African coast has since increased.